Yes, they do - it's pretty straight forward, and like I said, modx CAN populate the new field, just does not seem to be able to select data from it [it will select all the other columns though!]
The new field is the 'company' filed, and it does match the database....
<?php
$xpdo_meta_map['ArtistAudio']= array (
'package' => 'extdata',
'version' => '1.1',
'table' => 'artist_audio',
'extends' => 'xPDOSimpleObject',
'fields' =>
array (
'artistkey' => 0,
'label' => '',
'location' => '',
'bytes' => 0,
),
'fieldMeta' =>
array (
'artistkey' =>
array (
'dbtype' => 'int',
'precision' => '10',
'phptype' => 'integer',
'null' => false,
'default' => 0,
),
'label' =>
array (
'dbtype' => 'varchar',
'precision' => '255',
'phptype' => 'string',
'null' => false,
'default' => '',
),
'location' =>
array (
'dbtype' => 'varchar',
'precision' => '255',
'phptype' => 'string',
'null' => false,
'default' => '',
),
'bytes' =>
array (
'dbtype' => 'decimal',
'precision' => '10,0',
'phptype' => 'float',
'null' => true,
'default' => 0,
),
'company' =>
array (
'dbtype' => 'varchar',
'precision' => '255',
'phptype' => 'string',
'null' => true,
'default' => '',
),
),
'aggregates' =>
array (
'ArtistAttributes' =>
array (
'class' => 'ArtistAttributes',
'local' => 'artistkey',
'foreign' => 'id',
'cardinality' => 'one',
'owner' => 'foreign',
),
),
);